MIT Alters Naturally Occurring Proteins to Help Fight Superbugs

A team of researchers from the Massachusetts Institute of Technology, University of Brasilia and University of British Columbia has engineered naturally occurring proteins called antimicrobial peptides to kill many types of bacteria, including the so-called superbugs, which are resistant to most known antibiotics.

Their study, published in the journal Scientific Reports, focused on an antimicrobial peptide known as clavanin-A, which was originally isolated from a marine animal known as a tunicate. Clavanin-A, like other antimicrobial peptides, is known for its ability to destroy many types of bacteria. Additionally, antimicrobial peptides are also known to kill fungi and viruses as well.

"One of our main goals is to provide solutions to try to combat antibiotic resistance," said Cesar de la Fuente, a post doc at MIT and one of the lead authors of the study, in a press release. "This peptide is exciting in the sense that it provides a new alternative for treating these infections, which are predicted to kill more people annually than any other cause of death in our society, including cancer."

For the study, the researchers add a sequence of five amino acids into the clavanin-A, making it more hydrophobic. Naturally occurring antimicrobial peptides can be composed of 20 different amino acids. Furthermore, these proteins have a positively charged region that allows them to poke through bacterial cells and a hydrophobic stretch that allows them to interact and travel into cell membranes.

By making the clavanin-A more hydrophobic, the researchers hope that killing ability of the peptide would increase. Tests in mouse models showed that the addition of five amino acids really improve the bacteria-killing ability of the new peptide, which they dubbed as clavanin-MO.

Clavanin-MO was effective in killing strains of Escherichia coli and Staphylococcus aureus that are resistant to most antibiotics. The researchers noted that the new peptide can also be potent against many bacterial strains.

With the positive results of the clavanin-MO, the researchers are now trying to determine the mechanism behind the improved killing abilities of the engineered-peptide, compared to the naturally occurring one. Furthermore, the researchers also want to use the engineered peptide to other applications, such as catheter coatings and skin ointments.